Transmission fun - part 2

[DINOZR]

My 19 has a weird, sloppy 3-4 shift that happens about once every few days on its first 3-4 shift of the morning. A few days ago it was 17 degrees F outside--coldest the truck has ever seen. In the usual place this happens (slight downard slope, light throttle) instead of a sloppy 3-4 shift, when it went to shift into 4th it essentially free-wheeled for 2-3 seconds. Then the gear indicator next to the tach flashed back and forth between 1-4-1-4-1-4 and then finally 4th caught and it went. Have never seen it before or since.

A month ago I took it to the dealer for the sloppy 3-4 shift. They reprogrammed the TCM but found no physical transmission issues via a simple fluid analysis.

It's weird that the 1-4-1-4-1-4 thing sounds just like your behavior.

 

[JefferyGT]

What nightmares are made of...
You should just get a brand new transmission.

Sorry bro!! Awful.

 

[FordTechOne]

My 19 has a weird, sloppy 3-4 shift that happens about once every few days on its first 3-4 shift of the morning. A few days ago it was 17 degrees F outside--coldest the truck has ever seen. In the usual place this happens (slight downard slope, light throttle) instead of a sloppy 3-4 shift, when it went to shift into 4th it essentially free-wheeled for 2-3 seconds. Then the gear indicator next to the tach flashed back and forth between 1-4-1-4-1-4 and then finally 4th caught and it went. Have never seen it before or since.

A month ago I took it to the dealer for the sloppy 3-4 shift. They reprogrammed the TCM but found no physical transmission issues via a simple fluid analysis.

It's weird that the 1-4-1-4-1-4 thing sounds just like your behavior.

The 3rd to 4th shift feel is a normal characteristic of these transmissions when cold. Clearing the adaptive tables (which is all the dealer did) just resets the TCM’s learning cycle. The 1st/4th issue you experienced is definitely not a normal characteristic though.

 

[Jason Krakauer]

What nightmares are made of...
You should just get a brand new transmission.

Sorry bro!! Awful.

Yeah - I mean if I had the option, I'd go brand new... but w/ the Warranty Co. flitting the bill, they insisted on rebuilt. Plus side, my Transmission guy added in those upgrade Raybestos friction discs at no add'l cost... so if I get it sorted, should be better than new.

 

[JefferyGT]

Yeah - I mean if I had the option, I'd go brand new... but w/ the Warranty Co. flitting the bill, they insisted on rebuilt. Plus side, my Transmission guy added in those upgrade Raybestos friction discs at no add'l cost... so if I get it sorted, should be better than new.

Was it damaged when the motor was replaced?

 

[Jason Krakauer]

Was it damaged when the motor was replaced?

No - I mean it was acting hinky (hard shifts and hanging on that 1-3 shift) before the motor came out. I kinda chalked it up to the motor being bad ... but after I got it back it went downhill quickly. The 1/4/1/4 shift dance started a little after and then it just got worse, progressively.

 

[Jason Krakauer]

Update for anyone still reading here - put about 1,000 miles on the truck since the last tear down/rebuild ... and everything seems to be working really well (knock wood). I'm not having any trouble when the truck is cold, no hard-shifts, no hesitation or flare-shifting at speed. Did some highway mileage, up/down the foothills to the AT, and around town.

Genuinely think that bad drum was the cause of all this ... just remember that they replaced it w/ the same exact part #, which means it could be a lurking issue for any Gen2's.

 

[Badgertits]

The 3rd to 4th shift feel is a normal characteristic of these transmissions when cold. Clearing the adaptive tables (which is all the dealer did) just resets the TCM’s learning cycle. The 1st/4th issue you experienced is definitely not a normal characteristic though.

Is the tranny actually physically shifting from 1-4 4-1 or the display just going bonkers, may seem like a dumb question but based on the tach & lack of clanging/banging from sporadically jumping gears like that it doesn’t seem (at least from the vid) that the Tranny is truly doing what it’s telling you

and the fluid not getting circulated by the drum or solenoid ring gear seals or whatever they’re called was a known issue for the GM 8L80e &’that tranny behaved VERY similar to this GM code signed 10 speed

 

[Jason Krakauer]

Is the tranny actually physically shifting from 1-4 4-1 or the display just going bonkers, may seem like a dumb question but based on the tach & lack of clanging/banging from sporadically jumping gears like that it doesn’t seem (at least from the vid) that the Tranny is truly doing what it’s telling you

and the fluid not getting circulated by the drum or solenoid ring gear seals or whatever they’re called was a known issue for the GM 8L80e &’that tranny behaved VERY similar to this GM code signed 10 speed

No - there was a neutral-safe condition going on there... engine was freewheeling while the indicator was bouncing around. I don't doubt it wasn't engaging in any gear at that point. The issue was it went from gear engagement to this neutral-safe and you would just not move. And then once it did engage it'd dump to 6th and sit there in limp-mode.

The drum sleeve walking was (in the estimation of my transmission guy) causing fluid to spin up other gears since the fluid passages weren't lining up as intended w/ it moving. So the TCM was seeing speeds on on gears that weren't actually engaged and was trying to accommodate all of it. Throwing the whole thing into fail. But that's likely also why I had actual friction material abuse at a level you shouldn't see at only 70K miles. Throw off a variable as important as that and things don't set normally, clutches dragging or applied at incorrect speeds, solenoids failing, etc.